class_docstr: Conventional frontend structure for ASR.
  
  Stft -> WPE -> MVDR-Beamformer -> Power-spec -> Log-Mel-Fbank
class_docstr_tok: ["Conventional","frontend","structure","for","ASR",".","Stft","-",">","WPE","-",">","MVDR-Beamformer","-",">","Power-spec","-",">","Log-Mel-Fbank"]
code: def output_size(self) -> int:
      return self.n_mels
  
file_path: espnet/espnet2/asr/frontend/default.py
imports: import copy
  from typing import Optional, Tuple, Union
  import humanfriendly
  import numpy
  import torch
  from torch_complex.tensor import ComplexTensor
  from typeguard import check_argument_types
  from espnet2.asr.frontend.abs_frontend import AbsFrontend
  from espnet2.layers.log_mel import LogMel
  from espnet2.layers.stft import Stft
  from espnet2.utils.get_default_kwargs import get_default_kwargs
  from espnet.nets.pytorch_backend.frontends.frontend import Frontend
label_desc: Use image node_id 2 for calling the DefaultFrontend obj's underlying member method code with example usage: obj.output_size() and returns: self